The present invention relates to a drive train and to a wind power plant with such a drive train.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Conventional wind power plants normally include a tower, a mounting platform rotatably fastened to the upper end of the tower, and a drive train arranged on the mounting platform. The drive train includes a rotor driven by wind and fastened to a rotor shaft which is supported on a bearing block. The rotor shaft is connected to a gearbox input shaft of a gearbox by way of at least one connecting element. The output shaft of the gearbox is in turn connected to a generator rotor arranged in a generator housing. The generator is connected to a frequency converter which is designed to control the generator and to feed the energy produced by the generator into a mains supply.
During operation of a wind power plant, energy is drawn from wind flow by the rotor which is thus caused to rotate. The rotational movement of the rotor is transmitted via the rotor shaft to the gearbox, which increases the rotational speed. Generally, the generator can be designed smaller as the rotational speed increases. This would be desired in terms of both stability and cost of the wind power plant. The gearbox is normally designed in a multi-stage manner, with planetary gearboxes being primarily used in larger plants at least for slow rotating gearbox stages. The output shaft of the gearbox drives the generator, converting the mechanical energy into electrical energy, which is then fed into a mains supply by way of the frequency converter.
In order to lubricate tooth contact areas and/or bearings arranged within a gearbox housing, drive trains are usually equipped with a lubricating oil system which has an oil reservoir that is provided either within the gearbox housing or as an external oil reservoir in a direct vicinity of the gearbox, i.e., in relation to an imaginary parting line between the housing and the generator on the side of the gearbox. When using an external reservoir, gearboxes with a number of planetary stages without spur wheel stages are provided in particular, since adequate installation space for required oil quantity is not available in view of the absence of a spur wheel case.
In both instances, accommodation of an oil reservoir is generally very complex and expensive, since providing installation space is problematic.
It would therefore be desirable and advantageous to provide an improved drive train which obviates prior art shortcomings and yet is of simple and inexpensive structure while yet being reliable in operation.